LA-ICP-MS Trace Element Composition of Sphalerite and Galena of the Proterozoic Carbonate-Hosted Morro Agudo Zn-Pb Sulfide District, Brazil: Insights into Ore Genesis

The metal-rich Vazante-Paracatu Mineral Belt, in central Brazil, hosts the Zn-Pb sulfide Morro Agudo District Mesoproterozoic (1.3–1.1 Ga) upper carbonate sequence of Vazante Group. district is comprised deposit and Bento Carmelo, Sucuri, do Capão occurrences. This also Fagundes, Ambrósia Bonsucesso deposits (northern part) zinc silicate North Extension (southern part). structurally controlled, stratabound stratiform styles mineralization orebodies have been variably classified as sedimentary exhalative, Irish-type Mississippi Valley-type. In this study, laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) spot analyses sphalerite galena from revealed that red (interpreted last stage) has higher Fe Mn lower Bi, Co, Cu, Ge, Hg, Tl compared to other types sphalerite, whereas first generation (Gn-I) enriched Ag, Cd, Se depleted Cu relative later (Gn-II). paragenesis principal component analysis (PCA) ore mineral composition suggest Agudo, Sucuri mineralized zones formed by similar processes involving mineralizing fluids with various compositions, comprising two main elemental associations: (1) Fe, As, In, Mn, Sb, Ag; (2) Ga, Se. Carmelo distinguished PCA its unique dolomite-hosted elevated concentrations Hg likely distinct or processes. Temperatures for range 82 320 °C, calculated based on trace element sphalerite. compositions are consistent MVT deposits; however, fluid temperatures hotter than typical may reflect a geothermal gradient active advective flow during Brasiliano orogeny.